Institut d'Electronique Fondamentale, UMR 8622 CNRS, University Paris Sud XI , 91405 Orsay Cedex, France.
Nano Lett. 2014 May 14;14(5):2456-65. doi: 10.1021/nl5001295. Epub 2014 Apr 23.
We report on the demonstration of MOVPE-grown single nanowire InGaN/GaN core-shell light emitting diodes (LEDs) with a transparent graphene contact for hole injection. The electrical homogeneity of the graphene-contacted LED has been assessed by electron beam induced current microscopy. By comparing graphene-contacted and metal-contacted nanowire LEDs, we show that the contact layout determines the electroluminescence spectrum. The electroluminescence changes color from green to blue with increasing injection current. High-resolution cathodoluminescence on cleaved nanowires allows the location with high precision of the origin of different emitted wavelengths and demonstrates that the blue peak originates from the emission of the radial quantum well on the m-planes, whereas the green peak arises from the In-rich region at the junction between the m-planes and the semipolar planes. The spectral behavior of the electroluminescence is understood by modeling the current distribution within the nanowire.
我们报告了使用 MOVPE 生长的单根纳米线 InGaN/GaN 核壳发光二极管（LED）的演示，该 LED 具有透明的石墨烯接触以进行空穴注入。通过电子束感生电流显微镜评估了石墨烯接触 LED 的电均匀性。通过比较石墨烯接触和金属接触的纳米线 LED，我们表明接触布局决定了电致发光光谱。随着注入电流的增加，电致发光的颜色从绿色变为蓝色。在劈开的纳米线上进行的高分辨率阴极荧光允许高精度地确定不同发射波长的起源，并证明蓝色峰值源自 m 平面上的径向量子阱的发射，而绿色峰值则源自 m 平面和半极性平面之间的交界处的富 In 区域。通过对纳米线内电流分布进行建模，可以理解电致发光的光谱行为。
